Idea's From The Keyboard Of Lucy: Flood The Desert

With man made Climate Change really going up a notch now and the window for finding easy solutions is rapidly closing but to do nothing is suicide but runaway global warming where we all die is equally suicidal so we need some big ideas, and luckily i have one.
Actually, it isn't all my idea but i got it while watching pictures of the Sahara Deset flooding for the first time in over 50 years after heavy rains and i thought hang on, the 3,600,000 sq mile Sahara Desert is just sat there being all arid and useless, why not flood it?
Running all across the North Africa it is as large an area as the United States and has a population of 2.5 million people, less than 1 person per square mile, and it is something the French actually doing back in the 1870's after they finished the Suez Canal and actually investigated it and drew up plans although that was more to do with commerce rather than stop us all dying horribly.
'The Sahara is the cancer eating away at Africa and we can’t cure it therefore, we must drown it' said François Élie Roudaire who was tasked with seeing if it was feasible and discovered that there were large parts of the Sahara that were ancient seabeds and below sea level and he proposed connecting canals running from area to area across Africa.
The French Government went from Oui to Non when they heard the price, over 1 billion Francs (£892,617) and the Desert was left dry and full of sand but Roudaire's own figures estimated that his chain of canals and massive lakes in the old seabed would lower the Global sea level by between 3 and 5 centimeters and with the sea level rising by 3.6 mm per year, that's a decade of sea level rises reversed right there.   
Obviously someone would need to look into the possible unintended consequences of introducing the sea to somewhere which hasn't seen it for millions of years and there is the issue of the 2.5 million people who live there but maybe someone should pick up Roudaire's idea and have another look at it before its too late and evolution gives us flippers.